Suspended pipelines and other elongated rather slender bluff bodies are susceptible to the development of von Karman vortex streets and the resultant vibrations which may be induced by this vortex shedding phenomenon. Vortex shedding from suspended pipeline sections and similar cylindrical structures may be overcome by strengthening the pipe to change the natural frequency of the suspended section, providing more closely spaced supports or varying the support spacing. Alternatively, vortex breakers or spoilers may be provided in the form of helical ribs or strakes such as disclosed in U.S. Pat. No. 3,076,533 to C. Scruton and D. E. J. Walshe. Although the Scruton, et al, patent suggests the provision of helical rib-type vortex spoilers, the application of this type of spoiler to suspended pipelines presents certain problems, the solutions to which have eluded art workers prior to the development of the present invention.
For example, the installation of pipelines in remote regions and of various diameters, including those which are covered with insulating material, make it inconvenient or impossible to install conventional metal or preformed helical rib-type vortex spoilers. Accordingly, there has been a longfelt need to develop a type of vortex spoiler of the general type discussed hereinabove which may be easily attached to suspended pipelines after installation of the pipeline, may be readily adaptable to pipelines of different diameters, may be easily shipped to remote worksites for installation and is also relatively inexpensive to fabricate and install. These desiderata have not been provided by the configurations of vortex spoilers in the prior art. However, with a development of the present invention, substantially all of the improvements sought have been met with a surprisingly inexpensive and easily installed vortex spoiler system.